Sticky nanoparticles find tumor cells where they can be used to release drugs straight to the culprit

Building on past research with sticky nanoparticles, scientists at MIT have developed a method of delivering drugs straight to tumor cells. Previously the particles, which flow discretely through the bloodstream adhering only to tumorous cells, helped visualize tumors via magnetic resonance imaging. Now, using electromagnetic wave pulses, the same particles could be used to bomb the tumor cells with drugs.

The researches found that they could use the superparamagnetic properties of certain nanoparticles to activate, or in this case destroy, bonds holding drug molecules to the particles. Superparamagenetic materials have the property of giving off heat when exposed to a magnetic field.

The researchers used low-frequency wave pulses with frequencies between 350 and 400 kilohertz. These frequencies are much lower than much-feared microwaves, and pass harmlessly through the body, affecting only the nanoparticle delivery vehicles.

The microscopic drug tethers are made from strands of DNA. What makes the DNA molecule a good choice is that it can be created to melt with different amounts of heat based on strand lengths and coding. This could allow each particle to have several kinds of drug molecules attached to it, thus safely customizing treatment by simply modulated the pulse's frequency.

Though tests in the lab involving mice and implanted faux-tumors saturated with the drug bomb nanoparticles have been successful, the team of researchers is still doing work to guarantee that enough of the drug-ferrying particles will clump together inside of a tumor naturally to be effective.

"Our overall goal is to create multi-functional nanoparticles that home to a tumor, accumulate, and provide customizable remotely activated drug delivery right at the site of the disease," said Sangeeta Bhatia, M.D., Ph.D, an associate professor at the Harvard-MIT Division of Health Science and Technology and MIT's Department of Electrical Engineering and Computer Science.

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